This document discusses URL identifiers and solutions to problems with URLs not being persistent when resources move. It describes PURL and DOI as persistent identifier systems. PURL uses a resolver address and name component to redirect to current URLs. DOI assigns a persistent identification number to registered intellectual content and uses a DOI prefix and suffix. DOIs ensure persistence by resolving to current URLs through simple or multiple resolution methods.

1. Shriram Pandey
The LNM IIT, Jaipur

2. Background
 Resource Identification- A first step to gain access.
-Book: ISBN, UPC
-Periodicals/Journals-ISSN
 Similar Identification system also require for the
digital environment.

3. URL(Uniform Resource Locator)
 It is an address of the resource located anywhere over
the Internet.
 Uniform: Unique
 Resource: Anything that has entity
 Identifier: An object that can act as a reference to
something that has an identity

4. Component of URl
 Syntax: <scheme>:<scheme-specific-part>
 The scheme may be :
 ftp :File Transfer protocol
 http: Hypertext Transfer Protocol
 https: Hypertext Transfer Protocol Secured
 mailto: Electronic mail address
 telnet :Reference to interactive sessions
 File: Host-specific file names
Example: http://www.suniv.ac.in

5. Problem Associated with URL
URL are not persistence and resource can lost, if
 the server moves to a new computer
 the server moves to a new port on the same computer
 the name of the computer the server runs on changes
 the resource's name changes
 the resource moves to a new server

6. The Solutions
 A permanent URL which persistence.
 There are many solutions : PURL, Handle System, DOI
etc.
 We shall cover the PURL and DOI in detail.

7. PURL
 PURL(Persistent Uniform Resource Locator)
 A project by OCLC
 Three Component :
 Protocol
 Resolver address
 Name
 Example: http://purl.oclc.org/SU/PG_DLIS

8. How PURL Work

9. Digital Object Identifier
 An identification system for intellectual property in
the digital environment.
 Developed by the DOI foundation to provide a
framework for managing intellectual content, link
customers with publisher.
 Provides a persistent identification number to each
resource registered with DOI registration agencies.

10. Component of DOI DOI Prefix:
 Two component: 10.<organization assigned number>
 DOI Suffix
 Identification for the entity, it may be a number, ISBN etc.

11. DOI Resolution
 Ensures persistence by resolving the DOI to a current
associated value such as a URL;
 Resolution may be :
 Simple Resolution
 Multiple Resolution

12. Simple Resolution

13. Multiple Resolution

14. Benefits of DOI Systems
 Persistence, persistence, persistence!!!
 DOIs are easy to use. Simply click one or cut and paste
it like you would a URL
 Called the “barcode for intellectual property”
 Multiple resolution capability leads to more options
for researchers.